In various pneumatic systems and devices it is necessary to remove condensates and other foreign materials to insure proper operation. Various devices such as separators, filter traps, dryers, drip-legs, etc., are used for separating out and collecting condensates and other materials, and such devices are generally provided with drain valves for discharging the collected condensables from the pneumatic system or device. Many different drain valves have been devised for discharging the accumulated materials from pneumatic systems. For example, some drain valves are regulated by timers to automatically open the valve to periodically drain condensates which have been collected. Other drain valves open in response to a certain amount of condensates or other material being collected. One such drain valve system is disclosed in U.S. Pat. No. 4,574,829 issued to Ernie W. Cummings and Nick Valk such patent being a continuation-in-part of U.S. Pat. No. 4,444,217, issued Apr. 24, 1984, there being a previously filed continuation-in-part application resulting in U.S. Pat. No. 4,562,855, issued Jan. 7, 1986. The drain valve system of U.S. Pat. No. 4,574,829 comprises a reservoir for receiving condensates and other material from the pneumatic system. The reservoir of the drain valve is selectively drained by a valve connected to the outlet port of the drain valve's reservoir. In order to open and close the drain valve of the system, an external pneumatic valve operator is required, the valve operator being actuated by pressurized air selectively communicated to the valve operator by a magnetically controlled pilot valve. Still other of these known systems and devices for draining pneumatic systems are described in the background section of the above-identified patents and otherwise cited in such patents. Further, various drain valves marketed by Van Air Systems, Inc., Lake City, Pa. and Hankison Corporation, Canonsburg, Pa., are illustrative of prior art devices.
Therefore, it is an object of the present invention to provide an automatic drain valve for discharging accumulations of condensables and foreign materials present in pneumatic systems.
Another object of the present invention is to provide a drain valve for pneumatic systems which does not require an external valve operator.
Still another object of the present invention is to provide a drain valve which discharges condenates and other materials without expelling air or other gases from the associated pneumatic system.
A further object of the present invention is to provide an automatic drain valve which is self flushing so as to be essentially self cleaning.
Yet another object of the present invention is to provide an automatic drain valve which utilizes an internal pneumatic valve operator and an operatively associated linkage assembly for selectively opening and closing the drainage valve of the drain valve.
Still another object of the present invention is to provide an automatic drain valve which is inexpensive to manufacture and maintain particularly by virtue of its size.